1. Field of the Invention
The present invention relates to a method of determining a touch gesture and a touch control system, and more particularly, to a method of determining a touch gesture and a touch control system capable of easily determining a multi-touch gesture.
2. Description of the Prior Art
In general, an optical, a capacitive, or a resistive touch device may generate touch control signals corresponding to touch events performed by a user, and determine the touch events by the touch control signals. For example, when the user utilizes fingers to perform touch gestures with various sequences of pointing, clicking, dragging or moving, etc., on the touch device, the touch device may detect touch points corresponding to the fingers to generate the touch control signals. Then, the touch device determines positions of the touch points corresponding to the touch gestures according to the touch control signals.
For the optical touch device, detection of the touch points is performed by detectors, which are disposed around a screen of the optical touch device. Please refer to FIG. 1, which is a schematic diagram of a conventional optical touch device 10. As shown in FIG. 1, the optical touch device 10 may be an optical touch computer or an optical touch smart television, which comprise detectors 100-103, a screen 104 and four reflective bars 106 disposed around the screen 104. The screen 104 is utilized for displaying pictures and provided for the user to perform touch control and interaction according to the displaying pictures. The detectors 100-103 are disposed on four corners of the screen 104. The detectors 100-103 have light emitting elements (such as light emitting diodes) and may emit light (such as infrared light) to the reflective bars 106 around the screen 104 and illuminate the reflective bars 106. Simultaneously, the detectors 100-103 also have sensing components (such as charge coupled devices, i.e. CCDs) and may sense light reflected from the reflective bars 106.
Thereby, when touch objects (such as the user fingers) are touched on the screen 104, the light reflected from the reflective bars 106 may be blocked by the touch objects, and shadows are caused due to the blocking of the reflected light. At the same time, the detectors 100-103 may sense the reflected light from the reflective bars 106 to convert as signals. By determining waveforms and amplitudes of the signals, sharply falling positions of the waveforms may be founded to obtain positions of the shadows, so as to calculate positions of the touch objects on the screen 104.
In general, if only two detectors are respectively disposed on upper-left and upper-right corners of the optical touch device, only positions of two touch objects may be accurately analyzed and determined. In such a situation, when positions of more than two touch objects are wanted to be determined, more than two detectors are required for detecting the touch objects to obtain more signals corresponding to the touch objects, and the signals are also required to be determined by utilizing more complex algorithms, so as to accurately determine the positions of the touch objects.
As shown in FIG. 1, the user utilizes five fingers to respectively generate touch points TP1-TP5 (such as round solid dots in FIG. 1) on the screen 104. Regarding the detector 100, since the five fingers block the light reflected from the right-side and bottom-side reflective bars 106, shadows 110-114 are correspondingly generated falling on the reflective bars 106 due to the blocking of the reflected light. The detector 100 may sense the shadows 110-114 and analyze corresponding signals to obtain positions of the shadows 110-114. Similarly, regarding the detector 101, since the fingers also block the light reflected from the left-side and bottom-side reflective bars 106, shadows 120-124 are correspondingly generated falling on the reflective bars 106 due to the blocking of the reflected light. The detector 101 may also sense the shadows 120-124 and analyze corresponding signals to obtain positions of the shadows 120-124.
In such a condition, positions of the touch points TP1-TP5 may be determined by utilizing mathematical calculation. For example, line equations of light-blocked lines L1-L5 formed between the shadows 110-114 and the detector 100 and line equations of light-blocked lines L6-L10 formed between the shadows 120-124 and the detector 101 are calculated first. Then, cross points of the light-blocked lines L1-L5 and the light-blocked lines L6-L10 may be calculated and positions of twenty five detected points are obtained. The twenty five detected points comprise real points TP1-TP5 and other non-real detected points (such as round hollow dots), which are called as ghost points.
As can be seen, when the multi-touch gestures having more than two touch points are performed on the optical touch device, which only has the two detectors, the optical touch device only may obtain the positions of the detected points mixing the multiple real points and the multiple ghost points according to simple signal determining methods with the mathematical calculation. The optical touch device may not easily determine the real points among the detected points.
Thus, the conventional optical touch device requires utilizing more detectors for detecting and obtaining more signals corresponding to the touch points to determine the positions of the multiple real points according to intensity distribution or other features of the signals by the more complex determining algorithms. However, when more detectors are utilized, relatively higher hardware cost is required, and when the more complex determining algorithms are utilized, more powerful hardware logic circuits are also required for implementation.
Therefore, there is a need to provide an easily determining method for determining the multi-touch gestures.